OK S o what's the math to convert PPH to GMSps?

This book says 66lbs/hr x 453.6 gms/lb then x 1hr/3600 seconds... but mine does not come out close? Supposed to come up with 8.316 gms/sec...

I'm trying to convert 83.1 LBS/hr x 453.6 gms/lb then x 1hr/3600 seconds.